Suppress RUF027 fix for f-strings with comments targeting Python < 3.12

[FrederickStempfle]

Summary

• Suppresses the RUF027 autofix when the resulting f-string would contain comments inside interpolations, which is invalid syntax before Python 3.12 (PEP 701)
• Extends the existing backslash check to also cover # in interpolation text
• Also fixes a latent case in the existing test fixture (triple-quoted string with # comment inside braces)

Test plan

• Added test case from RUF027 creates invalid f-string interpolations with comments before Python 3.12 #23460 to RUF027_0.py
• Updated snapshots for both the main test and the py311 diff test
• All existing tests pass

Closes #23460

[ntBre]

Thanks for working on this, but it looks like there's another PR for this issue from yesterday: #23480. I'll close this for now and plan to review that one first.